Fabrication of 4H-SiC n-channel IGBTs with ultra high blocking voltage

Abstract

Owing to the conductivity modulation of silicon carbide (SiC) bipolar devices, n-channel insulated gate bipolar transistors (n-IGBTs) have a significant advantage over metal oxide semiconductor field effect transistors (MOSFETs) in ultra high voltage (UHV) applications. In this paper, backside grinding and laser annealing process were carried out to fabricate 4H-SiC n-IGBTs. The thickness of a drift layer was 120 μm, which was designed for a blocking voltage of 13 kV. The n-IGBTs carried a collector current density of 24 A/cm2 at a power dissipation of 300 W/cm2 when the gate voltage was 20 V, with a differential specific on-resistance of 140 mΩ·cm2.

A New SiC Planar-Gate IGBT for Injection Enhancement Effect and Low Oxide Field

“…A feasible fabrication procedure of the new SiC IGBT is proposed with a set of established process steps in conventional planar gate SiC IGBT [12,[41][42][43]. The proposed fabrication flow is illustrated in Figure 10.…”

“…SiC-based power devices have been widely studied and commercially available: for example, metal-oxide-semiconductor field effect transistors (MOSFETs), and junction barrier Schottky diode. For quite high voltage power applications (>10 kV), SiC insulated-gate bipolar transistors (IGBTs) are preferred since bipolar conduction mode in the IGBTs can efficaciously reduce the on-state energy loss [7][8][9][10][11][12][13]. In traditional silicon technology, the trench-gate IGBT is widely used due to its injection enhancement effect which increases plasma density in the drift region [14][15][16][17].…”

Retrograde p-Well for 10-kV Class SiC IGBTs

“…The 10kV class SiC IGBT research has gained significant momentum since the inception of the first 10kV p-IGBT on 4H-SiC in 2005 by Zhang et al, particularly, in the aftermath of realization of high-voltage n-channel devices on free-standing 4H-SiC epilayers in 2010 by Wang et al [4,5]. Extensive efforts have been put lately on realizing SiC IGBTs in the 10kV-30kV voltage range where they can offer a more favorable trade-off between the conduction and switching losses when compared with unipolar counterparts [6][7][8][9][10][11][12][13][14][15][16][17][18][19][20].…”

“…Although, the processing of n-channel IGBTs is particularly challenging, both the breakdown voltage and specific on-resistance have significantly improved due to important breakthroughs in bulk/epilayer growth and controlled post-process substrate grinding [21]. N-epilayers can be grown as thick as 200µm with a good control on the doping concentration in the range 1×10 14 -3×10 14 cm -3 [15][16][17][18]. Defect density is acceptable in terms of realizing devices with an active area of 1cm×1cm and the carrier lifetime (τ) is approaching ~12µs [21].…”

“…Defect density is acceptable in terms of realizing devices with an active area of 1cm×1cm and the carrier lifetime (τ) is approaching ~12µs [21]. N-channel SiC IGBTs have been successfully demonstrated up to a breakdown voltage of 27kV with continuous improvement in switching characteristics [17][18][19][20].…”